ASHLAND — The onset of cold weather may be bringing some unwanted guests to local homes and businesses.

Asian lady beetle infestations have been reported during the fall across Kentucky since the early 1990s. The bugs are not harmful to humans or their homes but simply a nuisance, according to experts.

Each year, Kentucky Division of Forestry workers field questions about the ladybugs from residents who want to know how to dispel the bugs or prevent infestations.

Jody Thompson, a forest health specialist with the Kentucky Division of Forestry, said it’s already too late this year for residents to stop the pests from invading.

“If they are going to do something to try to keep them from coming in, it has to be done early,” said Thompson. “For next year they will want to start sealing cracks probably before September.”

“When the weather starts to become more consistently cool in October, that’s usually when you see them invading the heaviest. They are looking for a place to hang out and not expend a lot of energy until the warm weather in the spring,” Johnson said.

According to an article published by the UK Cooperative Extension Service on Asian lady beetles, the bugs are attracted to illuminated surfaces and often congregate in the sunnier, southwest sides of buildings illuminated by afternoon sun.

Beetles tend to group in cracks, around windows and door frames behind fascia boards and exterior siding and within soffits, attics, and wall voids. Homes near woods and fields tend to be especially vulnerable to infestation, the article says.

Older homes in poor repair with lots of cracks and openings are the most susceptible to infestation.

Johnson said contrary to popular belief, the bugs do not cause structural damage to homes. “One thing they do do, is sometimes they will make these yellow stains where they were hanging out,” he said.

Once the beetles have found a winter home, they are hard to get rid off. Vacuuming the pests is seen as more sanitary and effective than insecticides, which can cause their own damage to homes.

UK entomologists report that insecticide foggers, “bug bombs” or sprays are generally not recommended for eliminating beetles indoors.

Fast-acting residual insecticides can be sprayed in targeted bands around windows, doors, eaves, soffits, attic vents and other likely points of entry. However, they must be applied before the beetles enter buildings.

Prevention, according to Johnson and experts, is a better approach. Sealing cracks and openings is the most effective way to prevent beetles from entering.

According to Johnson, there are a number of myths the public holds about the lady beetles, including that they bite humans and mate during the winter.

Both are untrue.

“That is not a part of their behavior to bite humans,” said Johnson. “They do not mate inside homes. They mate outside. Its thought that is only in the spring when they are leaving wherever they are hanging out,” he said.

Winter infestations of Asian lady beetles or lady bugs were first reported in Kentucky during the early 1990s.

Johnson said the biggest myth about the bugs is that the Division of Forestry releases the beetles for agricultural purposes each year. This is also not true.

According to extension entomologists, between the 1960s and 1990s the U.S. Department of Agriculture attempted to establish the Asian lady beetle to control agricultural pests and released large numbers in several states.

“Kentucky was not one of the states,” said Johnson.

The fact the bugs are now here is thought to be a result of their northward migration from other Southern states.